This invention relates to an amide derivative and an external medicament comprising such derivative and, more particularly, to external medicament capable of enhancing the moisture retainability of keratin layers thereby improving chapping of the skin. 2. Description of the Prior Art
It has hitherto been known that water content in keratin layers is an important factor for moistening and softening skin. It is considered that the water content is retained by water-soluble ingredients contained in the keratin layers, i.e., free amino acids, organic acids, urea or inorganic ions. These substances are incorporated solely or in combination into pharmaceutical external medicament or cosmetic composition in order to improve or prevent chapping of the skin.
Aside from the foregoings, many moisture retaining substances having high affinity with water have been developed and used for the same purpose.
However, these moisture retaining substances, when applied to the skin, remain on the keratin layers of the skin, serve to supply water thereto and act only temporarily thereby providing no fundamental improvement for the water retainability of the keratin layers or essential prevention or cure of chappings in the skin.